Chauncey b



FFIQE,

CHAUNCEY B. FORWARD AND JOHN M. DAVIDSON, OF CLEVELAND, OI-IIO,ASSIGNORS TO THE FORW'ARD REDUCTION COMPANY, OF

NEW YORK, N. Y.

METHOD OF OBTAINING ASPHALT FROM CRUDE PETROLEUM AND PETROLEUM-TARSPECIFICATION forming part of Letters Patent No. 61 1,620, dated October4, 1898,

Application filed December 18, 1897. Serial No. 662,484! (No specimens.)

To (LZZ whom it may concern:

Be it known that we, CHAUNOEY B. FOR- WARD and JOHN M. DAVIDSON,citizens of the United States, residing at Cleveland, in the county ofOuyahoga and State of Ohio, have invented certain new and usefulImprovem ents in Methods of Obtaining Asphalt from Crude Petroleum andPetroleum-Tar and we do declare that the following is a full, clear, andexact description of the invention, which will enable others skilled inthe art to which it appertains to make and use the same.

0 ur invention relates to a method of obtaining asphalt from crudepetroleum and petroleum-tar, and also to a method of refining orreducing crude petroleum, so as to obtain asphalt as one of the resultsof the process.

Crude petroleunr-that is, petroleum as it comes from the well-consistsof a mixture of oils of various qualities from the lightest and mostvolatile down to the heaviest or most fixed of oils, with a blacksubstance, which consists very largely of carbon. In this crude statethe petroleum is not capable of much economic use except asa cheap fuel.

a The refining or reduction of crudepetroleum as heretofore practicedconsists in the separation of these various grades of oils from theblack or carbonaceous matter, their separation from each other, andtheir purification. The usual process now adopted is distillation. Thecrude oil is subjected, under proper conditions in stills, to varyingdegrees of heat, and the oils pass off through the worm of the still andare then recondensed. A small degree of heat sends off the lighter oils,and as the heat is increased the various grades of heavier oils are sodistilled off. The heavier the oil the greater the degree of heatnecessary for its distillation off from the mass. The final residuumleft after all this distillation is a hard cokey substance calledpetroleum-coke, which is sometimes used for fuel and for other purposes,but which is of little value, owing to the fact that the great heatnecessary to drive off the heavier oils in the process of distillationhas in a great measure taken away from this substance its beneficialqualities. The distillation by which the heavier oils are driven off isa destructive distillation. It also results that during this process ofdistillation a considerable part of the black or carbonaceous matter isdriven off with the oils-less with the lighter oils'than with theheavier oilsthe degree of heatto which the mass has to be subjected whenthe heavier oils are driven off being such asto drive oif also much ofthe lighter or more volatile parts of. the carbonaceous matter. It isnecessary to treat theseoils after their distillation as above describedin order to purify them from this carbonaceous matterand other foreignsubstances.

By our improved process we take either the crude petroleum as it comesfrom the well or after the lighter oils have been distilled therefrom,but'before the process of distillation has been carried far enough tobecome destructive. hat is left after the lighter oils have beendistilled off is known by the name of petroleum-tar or residuum-oil,"and we mix this in agitators or other receptacles with acid. Sulfuricacidthe oil of vitriol of commerce-is well adapted for this purpose andis cheaper than most other acids, so that we use it in preference. Thequantity of acid used for a given quantity of the crude petroleum orpetroleum-tar depends somewhat upon the nature of the crude petroleum orthe petroleum-tar.

The crude petroleum of the Ohio and Indiana fields contains more of thecarbonaceous matter than the crude petroleum of the Pennsylvania fields,and the crude petroleum from each particular field or locality differssomewhat in the relative proportion of its constituents. The more of thecarbonaceous matter contained in the material treated the greater is theamount of acid required, and the petroleum-tar, containing, as it does,a greater percentage of thecarbonaceous matter than the crude petroleumitself before the lighter oils have been taken off,- requires a largerpercentage of acid than the crude petroleum from which it is derived,and the more oil that has been taken oif the greater the percentage ofthe carbonaceous matter in the tar or residuum will be and the greaterthe amount of acid required. It is not necessary to regulate the amountof acid used with any great degree of nicety, because the acid isinexpensive and most of it is afterward recovered back, and the use ofmore than is necessary within limits does no harm. It is best toregulate the quantity used by experiment with the particular material orresiduum under treatment, being sure to use enough. Generally speaking,the amount of acid will vary from eight per cent. to twenty per cent. ofthe amount of the crude petroleum or petroleum-tar under treatment,eight per cent. or fourteen per cent. being sufficient when ordinarycrude petroleum is being treated and from twelve percent. to twenty percent. be ing required for the best effect when the petroleum-tar isbeing treated. It will rarely, if ever, be found necessary to use morethan twenty percent. It is easy, by a little experience in theparticular material under treatment, to regulate the percentage of acidwhich it is best to use. The materialis then heated in the agitators andthoroughly agitated. If the crude petroleum as it comes from the well isunder treatment, the heat should not exceed about else a considerablepart of the lighter oils will pass off in vapor.' If the petroleum-taris being treated, the heat may be as high as or without injury. Intreating the crude oil we prefer to take off by distillation some, atleast, of the lighter oils first, because it enables us to use a greaterdegree of heat in the agitating process and the results are moresatisfactory. After this material in the agitators has been so heatedand agitated it is allowed to settle. It will be found that the acid hasunited with the carbonaceous matter, and as the material in theagitators settles this combination of the carbonaceous matter and theacid is precipitated to the bottom, and it or the clear material abovemay be drawn 01f and thus the oils separated from the carbonaceousmatter. The oils so freed from the carbonaceous matter which was beforecontained in them should be thoroughly washed, so as to remove anyremaining acid therefrom. The process of washing is well known. Thematerial to be washed is thoroughly mixed with alkaline water-it isbetter to be hot-and then, upon settling, the oil rises to the top andthe water carrying the acid sinks to the bottom. The oil may be drawnoff from the top of the tank or agitat-or and the water containing theacid drawn off from the bottom, and thus they are separated. The acidmay be then separated from the water and saved bya process ofdistillation which is Well understood. \Ve have now remaining thecarbonaceous matter, previously contained in the crude petroleum or thepetroleum-tar, mixed with the greater portion of the acid which has beenused in the treatment. It is from this substance that the asphalt orbituminous product is made. We first wash it to separate the acidtherefrom. The process of washing this is similar to that employed inwashing the oil, and the result is that the water containing the acidsinks to the bottom and the carbonaceous matter, substantially clear ofthe acid, rises to the top, and the carbonaceous matter may be drawn offfrom the top or the water from the bottom and so separated. This acidcan be recovered from this water by the same process of distillation asbefore mentioned. t is usually best to repeat this washing process twoor three times in order to more thoroughly remove the acid from thecarbonaceous matter. Most of the acid will be recovered in the firstwashing; but some of it will always remain to be taken out by a secondand third washin g, and its presence in the carbonaceous matter in anyconsiderable amount is injurious. We now have the carbonaceous matterwhich was originally in the crude petroleum or petroleum-tar with theoil and the acid removed. Some portion of the oil will adhere to thecarbonaceous matter, and its presence is beneficial rather thanotherwise and some traces of the acid may remain; but if the washing hasbeen thorough there will not be enough to do any harm. This material byitself will not make the best grades of asphalt. It contains too large aproportion of volatile matter. For the best result it is necessary tomix it with some heavy oil. The heavy hydrocarbon oil, one of thewellknown products of any system of petroleu mrefining, answers thispurpose very well and is very cheap. Under our process such oil will beproduced from the mixture of oils which remains after the carbonaceousmatter has been separated therefrom by the acid treatment, being theproduct remaining in the still after all lighter oils have beenseparated from said mixture by distillation, and under the treatmentheretofore employed in petroleum-refining it will be produced as thelast product of distillation. The heavier the oil the better, and itmakes no difference whether or not it hasv been treated so as to purifyit. All that. is necessary is that it should be a very heavy oil, andsuch oil as we need is quite inexpensive.

The proportion of heavy oil to the carbonaceous matter may varyaccording to the character of the material to be mixed with it and ofthe product required, as will be hereinafter more particularlyexplained. 4 This heavy oil and the carbonaceous matter are thenthoroughly mixed. The mixture may be effected by any mechanical meansadapted to the purpose. The mixture is then subjected to a high degreeof heat, preferably as high as 800 Fahrenheit. This heat should be keptup for from four to eight hours. During the heating such mechanicalchanges or chemical reactions take place as to convert the combinedmaterial into a superior grade of asphalt, and the process may in somecases be terminated at this stage; but for many purposes the asphalt isimproved and the products made cheaper by the addition to it of thecarbonaceous matter; but these PI'O';

portions may vary. The carbonaceous mat ter is not always of exactly thesame constituency. That obtained from one oil-field will differ fromthat obtained from another, and the carbonaceous matter obtained fromthe petroleum-tar after the lighter oils have been distilled away is alittle different from that obtained from the crude petroleum, for thereason that in the distillation of the lighter oils some of the morevolatile parts of the carbonaceous matter have been distilled away withthem, and its character varies somewhat according to the amount of acidemployed and the care with which it has been removed, as well as thethoroughness with which the separation between the oil and thecarbonaceous matter has been effected. The percentage of heavy oil tocarbonaceous matter also depends in some degree upon the character ofthe oil employed. The heavier the oil the less of it is necessary,because it is the heaviest part of the oil that produces the beneficialresult. Exaetitude in the percentage between the oil and thecarbonaceous matter is not necessary. Generally speaking, the heavierthe carbonaceous matter isthat is, the more its more volatile portionshave been removed-the more oil should be used, and the more elastic andpliable the manufacturer desires the asphalt to be the more heavy oilshould be used. The proportion of twenty-five per cent. of oil toseventy-five per cent. of carbonaceous matter will always produce anasphalt of high grade, and it will not be found necessary to vary in anyconsiderable degree from these percentages.

The degree of the heat to which the mixture of the carbonaceous matterand the heavy oil is subjected and the length of time to which it issubjected to that heat also depend somewhat upon the character of thematerial used and ot' the result required. The heatshould be continuedlong enough to effeet the desired change in the substances. A good testof whether or not sufficient heat has been employed is to take out asample of the substance and subject it to the action of water. If theheat has been employed long enough, water will not disintegrate it. Ifnot, it will. After the heating process has been. continued for theproper length of time one can handle it as he can chewing-gum,

purpose for which it is to be used. The marl gives it weight, body,consistency, and tensile strength. For asphalt designed for ordinarystreet paving it will be found advisable to add about twenty per cent.of marl. For some purposes as much as thirty per cent, or even a verymuch higher percentage may be added. A mixture of marl and the asphaltas it is produced at the end of the heating process in the ratio ofabout three parts of marl to one part of the asphalt makes a mostexcellent and durable paving-brick.

For a cheaper grade of asphalt the heavy oil may be entirely omitted. Inthis case the carbonaceous matter should be subjected to the sametreatment by heat as we have described for the mixture of thecarbonaceous matter and the heavy oil, except that it cannot besubjected to as high a degree of heat, because that degree of heat wouldbe destructive of the substance if the oil was omitted. 600 Fahrenheitwould be as high a degree of heat as it would be safe to employ withoutthe oil. If marl is added, it should be .at the close of the heatingprocess in the same way as we have described when the heavy oil is used.If the oil has been omitted, the marl may be used more freely, becausethe product will be of a cheaper grade any way, and more marl may beused without depreciating the quality of the result.

Marl is mostly carbonate of lime, and lime in any other form may be usedinstead of marl, but the cheapness of marl makes its use preferable, andits use gives the best results.

What we claim is- 1. The process of making asphalt from crude petroleumby treating the crude petroleum with acid to separate the carbonaceousmatter from the oils, washing the carbonaceous matter to free it fromthe acid, then mixing it with heavy hydrocarbon oil and subjecting it toa high degree of heat for a considerable period, substantially asdescribed.

2. The process of making asphalt from petroleum-tar or from crudepetroleum after the lighter oils have been distilled 01f by treating itwith acid to separate the carbonaceous matter from the remaining oils,washing the carbonaceous matter to remove the acid, then mixing it withheavy hydrocarbon oil and subjecting the mixture to a high degree ofheat for a considerable period, sub stantially as described.

3. The process of refining or reducing crude petroleum by treating itwith acid to separate the mixture of oils obtained by this process intooils of various kinds by successive distillations, by mixing thecarbonaceous matter separated as above from the oils. with heavyhydrocarbon oil and subjecting the mixture to a high degree of heat fora considerable period, substantiallyas described.

4. The process of making asphalt from crude petroleum by first treatingthe crude petroleum with acid to separate the carbonaceous matter fromthe oils, then adding to said carbonaceous matter a heavy hydrocar bonoil and subjecting the same to a high de gree of heat, and then addingmarl or lime, substantially as described.

5. The process of treating petroleum-tar or petroleum after the lighteroils have been removed by distillation, by using acid to separate thecarbonaceous matter from the remaining oils, by mixing the same With aheavy hydrocarbon oil and subjecting the mixture to a high degree ofheat and then adding marl or lime, substantially as described.

6. The process of producing asphalt from crude petroleum orpetroleum-tar by treating the same with acid to separate thecarbonaceous matter from the oils, then subjecting this carbonaceousmatter to a considerable degree of heat for a considerable period,substantially as described.

Witnesses for Forward:

H. T. FISHER, ALBERT B. BLAcKWooD.

\Vitnesses for Davidson:

H. T. FISHER, II. E. MUDRA.

